TAS-103 is a dual inhibitor of DNA topoisomerase I/II, utilized in cancer research.

TAS-103 acts as a dual inhibitor of DNA topoisomerase I and II, demonstrating potency across various cell lines. Specifically, it shows activity against CCRF-CEM cells within a concentration range of 0.1-10 μM, achieving an IC50 of 5 nM, and notably enhances topo IIα FITC immunofluorescence at a concentration of 0.1 μM[1]. It exhibits pronounced cytotoxic effects on Lewis lung carcinoma (LLC) cells across a 0.01-1 μM concentration range, with both its liposomal and free forms displaying nearly equivalent activity[2]. Additionally, TAS-103, at an IC50 of 40 nM, significantly reduces the viability of HeLa cells. At a concentration of 10 μM, it interferes with signal recognition particle (SRP) complex formation, leading to the destabilization and degradation of SRP14 and SRP19 proteins[3].

TAS-103 (30 mg/kg, i.v.) significantly suppresses tumor growth in mice with Lewis lung carcinoma (LLC) cells without noticeable body weight loss. Moreover, liposomal TAS-103 shows greater efficacy than its free form[2].

CCRF-CEM human acute lymphoblastic leukaemia cells are grown in RPMI-1640 supplemented with 3 mM l-glutamine, 10% foetal bovine serum, 50 U/mL of penicillin, and 40 μg/mL of streptomycin at 37°C in a humidified atmosphere containing 5% CO2. TAS-103, CPT and DACA are dissolved in DMSO. Exponentially growing cells (～5 × 105) are exposed to either of the drugs for 2 hrs. Following drug exposure, cells are washed twice by centrifugation (400 × g, 3 min) in cold phosphate-buffered saline[1].